Improvement in the modes of casting wheels and pinions



F. R. WHEELD ON.

Mode of Casting Wheels and Pinions.

I No. 131,486. Patented Sep.17,1872.

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UNITED STATES PATENT OFFICE.

FREDERICK RICHARD WHEELDON, OF- WOLVERHAMPTON, ENGLAND.

IMPROVEMENT IN THE MODES 0F CASTING WHEELS AND PINIONS.

Specification forming part of Letters Patent No. 131,486, dated September 17, 1872.

molds, technically called chills, are sudden I y cooled or chilled,- and thereby acquire the property of great hardness, similar to steel or case-hardened wrought-iron, and by a suitable selection of pig-iron this hardened surface can be obtained of any required depth.

The nature of my invention is to avail myself of this property, and to construct such molds for casting partly of sand and partly of iron, sothat the molds of such parts of the castings as are not required to be hardened are formed of sand, while the molds of the other parts which are required to be hardened are formed of iron.

In molding wheels and pinions I make of cast-iron those portions of the molds which form the teeth or other parts of the wheel or pinion, whose surfaces being subject to great wear, it is desirable should be hardened; at the same time such hardness is not allowed to penetrate too deeply into the casting, which would make it brittle.

By my invention wheels and pinions can be made of gray iron possessing great strength and tenacity, while the surfaces only are hardened to any required depth.

That my invention may be fully understood I have annexed a drawing hereto, which I now proceed to describe, and which will illustrate my method of carrying out my said invention.

Figure 1 shows a vertical section of a mold for a pinion suitable for a mill for rolling wire or hoop iron. These mills are generally driven at a velocity of from two hundred and fifty to five hundred revolutions per minute; and, in consequence of this very high ve1ocity,the teeth of ordinary pinions become very quickly worn away. The parts marked 0 represent those portions of the mold which are made of sand;

those marked D represent the iron chills. E is the head-box for pouring in the fluid iron. At E is the runner or gate for conveying the iron into the mold. G is the open head left for the purpose of feeding the casting by pouring in hot fiuid iron during the time the shrinkage or contraction is goingon in cooling.

Fig. 2 shows a section of the mold through the line A B in Fig. 1, and it will be observed that the chills or parts of the mold in'which the teeth of the pinion are cast are formed in sections or segments for facility of removal from the pinion when cast. In those cases where a flange or shroudin g is cast on the pinion at each end of the teeth the casting would be liable to be ripped or torn bythe resistance which the iron chills in the mold-offer to the free contraction of the pinion in cooling. To obviate this I make use of the following devices:

Figure 3 is a section of an iron mold forming the teeth of the pinion. At F F it will be observed that the teeth arebeveled. When the hot iron is poured into the mold the chill,

becoming heated, expands and increases in diameter, thereby causing the beveled ends of the teeth to recede from under the flanges or shrouding of the pinion casting, so as to allow room for the contraction of the casting. In cases where the teeth of the pinions are to be made very long, I adopt the plan of recessing the ends of the teeth of the iron-chill, as shown on the upper part of Fig. 3 at H H, and this recessed part is filled in and made level with sand, so that, when the cast pinion begins to contract, the sand which is interposed is crushed, and the ripping or tearing of the casting is thereby prevented.

Fig. 4 is a plan showing the method I adopt in forming the chills. O G G O is a sand mold made in an ordinary box and forming the outside of the chill-castin g. J is a core formed of sand or iron, but I prefer to adopt the latter, which then becomes simply an accurately-molded cast-iron pinion filed smooth and laid in to the mold. Around this into the space shown by the unsh aded portion of the drawing the metal is run for casting the chills. Into this space I previously insert flat pieces of iron, shown at I I I, opposite each tooth of the core, the ends of such pieces of iron being sharpened and 2 isinsse forced into the sand, which forms the bed of the mold. When cold the casting is taken out, and after the ends have been turned or faced, and the teeth beveled or recessed at F or H, Fig.6, as before described, the outside is turned, and the parts D D D are then separated by being broken through at those places where they are already partially divided by means of the pieces of iron I I I. When placed together again for use the parts D D D will accurately fit each other at their broken surfaces, and being then firmly held together by two iron hoops, K K, Fig. 3, they are ready to be placed in the molding-box, as shownat D, Fig. 1. W V 7 Fig. 5 shows a plan of the four chills which form the bottom Wobbler, and marked L, Fig. 1.

Fig. 6 shows a plan of the method I adopt in placing the chills in the sand mold for larger pinions or wheels. Two different forms of chills are shown, as I find it sometimes convenient to vary the form of them to suit circumstances. As many chills will be required as there are teeth in the wheel. These chills are rammed up in the sand against the pattern or segment, of a pattern, from which the wheel or pinion is being made.

Fig. 7 shows a vertical section of the chills.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The sand mold 0, combined with and arranged in respect to the iron chill D, as set forth, for casting Wheels, pinions, &c.

2. The sectional iron chill D and movable strips, in combination with the sand mold O, as and for the purpose set forth.

3. Casting wheels and pinions by means of the sand mold O and iron chill D,head-box E, and runner E, combined with the open head G for introducing hot fluid iron during contraction in cooling, all arranged in respect to each other, substantially as herein shown, and for the purpose specified.

FREDERICK RICHARD \VHEELDON.

Witnesses:

SAMUEL ToY, BENJAMIN FORD. 

